I. Field of the Invention
The present invention relates to a sonar system of the flasher-type that is capable of displaying the bottom of a body of water and fish swimming in a body of water. More specifically, the present invention relates to a fish finder that is capable of selecting certain segments of the body of water and displaying representations of the fish swimming in that segment.
II. Description of the Related Art
Flasher-type fish finders have been available for many years. These systems universally include an ultrasonic transducer. The transducer performs several functions. First, it transmits sonar pulses in response to signals it receives from an oscillating circuit. The transducer also senses the return of the sonar pulses and, whenever it senses such a return, transmits a signal to a receiving circuit. Prior art flasher-type fish finders also include a control circuit that controls the oscillating circuit and processes signals it receives from the receiving circuit via an analog-to-digital converter. The controller processes these signals to determine the depth of the water and the depth at which fish are swimming. The controller also sends signals to a flasher display so that the depth of the body of water and the depth at which the fish are swimming can be displayed.
Flasher-type fish finders get their name from the type of display that is used. The display typically includes a housing having a ring-shaped window formed in the front. Mounted within the housing is a motor that turns a disk on which a light source such as a light emitting diode (LED) is mounted. Also mounted within the housing is a sensor that detects when the light source is at the top of the display.
The controller sends a signal to the oscillating circuit which, in turn, causes the transducer to emit an ultrasonic signal which propagates through the water. These ultrasonic signals xe2x80x9cbouncexe2x80x9d off of the bottom of the body of water and objects in the water and are returned to the transducer. The receiving circuit amplifies the returned signals. The amplified returned signals are converted to digital signals by the analog-to-digital converter and then delivered to the controller. Finally, when the sensor detects the light source is at the top of the display the controller delivers signals to the display whereby the depth of the bottom and objects such as fish in the water are displayed.
Prior art flasher-type fish finders of the type described above have proven to be economical and useful devices. However, they do not permit a user to carefully study in detail the number of fish swimming at a particular depth in the water. In other words, the typical flasher-type fish finder does not permit the user to zoom in and carefully study activity in particular depth ranges. While other fish finders have display systems (such as CRT or LCD type display systems) that do permit such study, there still exists a real need for a real-time fish finder that can provide such functionality.
The present invention provides a real-time flasher-type fish finder with a xe2x80x9czoomxe2x80x9d feature. Specifically, the fish finder of the present invention divides the flasher display in half, displaying standard information on one-half and information related to activity in a selectably specified depth range on the other half of the display. For example, the user can select a depth range of interest and then define the size of the window at that depth range which is of interest. One side of the display reports all of the information generated. The other side of the display only reports returns falling within the selected window surrounding the selected range, for example, activity occurring with a 10 foot window surrounding a depth of 80 feet.
The manner in which the present invention performs this xe2x80x9czoomingxe2x80x9d function will be understood by those skilled in the art from a review of the following detailed description of the preferred embodiment.